Can sorting machine



NOV. 3, F M JOHNSON ETAL CAN SORTING MACHINE Filed June 9, 1949 4 Sheets-Sheet l unI @u Y' IIAl QJ: m

NOV- 3, 1953 F. M. JOHNSON ET AL CAN SORTING MACHINE 4 Sheets-Sheet 2 Filed June 9, 1949 Nov. 3, 1953 2,657,799

F. M. JOHNSON ET AL CAN SORTING MACHINE Filed June 9, 1949 n 4 Sheets-Sheet 3 Nv 3 1953 F. M. JOHNSON ET AL CAN SORTING MACHINE 4 Sheets-Sheet 4 Filed June 9, 1949 vom@ INVENToR Mja/v2.5@

Patented Nov. 3, 1953 CAN SORTING MACHINE Frederick M. Johnson and Leander J. Bulliet, Rockford, Ill., assignors to Odin Corporation, Chicago, Ill., a corporation of Illinois Application June 9, 1949, Serial No. 98,112

6 Claims.

This invention relates to container handling equipment, and concerns more particularly a machine for sorting cans or jars in reference to indicia carried thereby.

In canned food preparing plants, certain cooking or sterilizing processes are carried out after the cans are filled and sealed but before identifying labels are applied. In many cases, economical production requires that two or more products, or qualities of the same product, be mingled together in these processes after sealing and before labeling. It then becomes necessary to sort out the several grades, the term .grade being used generally to designate any characteristic according to which the cans are to be segregated, and direct them to their respective labeling machines.

It has been customary in the canning industry to premark the cans in some suitable manner before filling and to place all products of a certain grade in cans of the same marking, while each other grade goes into cans of a different marking. Then, after cooking or sterilizing, the cans pass before employees who visually identify the grades by the can markings and manually place all of a certain grade on its respective conveyor leading to the proper labeling machine.

The visual and manual sorting of grades requires a large amount of labor and the canning industry has long felt a need for a device to perform this sorting function mechanically.

In accordance with the present invention, an automatically operable sorting machine is provided for effecting a sorting of containers, such as cans or jars, accurately and at high speed, in accordance with indicia carried thereby, and preferably which has been placed thereon in a predetermined position so as to differentiate each grade of cans from other grades provided.

It is an object of the invention to provide an automatically operable machine for effecting the sorting of containers, such as cans, jars, or the like, of improved construction and improved operating characteristics.

More particularly stated, it is an object of th present invention to provide a machine of the character described which is reliable in its operation, and which is operable in a reliable manner at high speed.

A'further object of the invention is to provide `a rsorting machine of the type defined which is operable to effect a separation of the containers in accordance with visual indicia carried thereby, of predetermined character and location.

A still further object of the invention is to Z provide a machine of the character defined, particularly adapted for operation in the sorting of food containers and the like, of cylindrical shape.

Various other objects, advantages and features of the invention will be apparent from the following specification, when taken in connection with the accompanying drawings, wherein certain preferred embodiments of the invention are set forth for purposes of illustration.

In the drawings wherein like reference nu merals are used throughout:

Fig. l is a side elevation of a sorting machine, constructed in accordance with and embodying the principles of the present invention;

Figs. 2 and 2A are illustrative views, showing the manner in which the containers may be marked for use with the machine illustrated in Fig. 1;

Fig. 3 is a transverse sectional view of a portion of the machine of Fig. 1, taken as indicated by the line 3-3 of Fig. 6;

Fig. 4 is a view similar to Fig. 3, but showing the parts in a different position of operation;

Fig. 5 is a top view of the machine of Fig. 1;

Fig. 6 is an enlarged view of one of the sec# tions of the machine of Fig. 1, Fig. l illustrating a three-section machine;

Fig. 7 is a horizontal sectional view of a part of the mechanism of Fig. 6, taken as indicated by the line 'l-l thereof;

Fig. 8 is a detail illustrative view showing the switch arm and associated parts, forming a part of the mechanism of Fig. 6, on a further enlarged scale; and

Fig. 9 is a wiring diagram for the machine, particularly illustrating the wiring connections for one visual sensing head.

Referring more particularly to the drawings, one method of marking the cans is shown in Fig. 2 where l designates a can marked for, let us say, grade A. On this can is stenciled a stripe 3 which may be in black ink and which preferably completely encircles the can near one end. rlhe numeral 5 is a can marked for grade 13. Around this can is the stripe 1 near the middle. The numeral 6 is a third typical can marked with a stripe 8 at a location approximately midway between the locations of stripes 3 and l. If there are more than three grades to be sorted, their respective cans may be striped at other definite locations relative to the ends of the cans. In accordance with the present invention, these cans may come intermingled from the cooker, and be identied and sorted according to the locations of their stripes.

Referring to the structure of the machine illustrated, as shown in Fig. 1, the machine comprises three sections of duplicate structure, it being understood that as many sections will be provided as there are can grades to be sorted in any particular installation. Referring in detail to the structure of the iirst section, in Figs. 1, 3 and 4 the numeral 9 designates a chute consisting of a door plate II, two wall members I3, and a top plate I5. The top plate is bolted to the wall members. The oor plate is fitted into rabbets I1 in the wall plates I3. The wall plates 13 .are held together against the edges of noor II by through-bolts I4. Each Wall plate i3 has an S-shaped aperture I9 cut through it as best shown in the enlarged View, Fig. 6.

On each side of the chute 9 is a pivoted gate 2|. A lower flange member 23 of each gate ZI is S-shaped to fit loosely into the aperture I9.

Each member 23 is supported by a pair of side an's or members 25 'and 21 which are fixed to a shaft 29. Each shaft 2 9 is journaled for rotation inbe'aring blocks 3'I and 33, Fig. '6, which are-'welded to a motor plate 35. In turn, the motor plate 35 is welded to brackets 31 and 39 which are welded to the chute top plate I5.

The upper end 4I of each gate side armor member 21 is forked at 43 to receive a link 45. The links 45 are connected to the arms 4I by the pins '41 which are pressed tightly into holes in the arms 4I but are loose in bearing holes through the linksv45. A crank arm 49 iskeyed to the rotor shaft U 'of a torque vmotor 5I. The crank arm 49 is forked at its ends to receive the links 35 lwhich are connected to the crank arm by pins L53vs/l'lich are tight in the crank arm and loose in the links.

Rotation of the motor shaft 5I.) -clockwisea's seen in Fig. 3) will pull the arms 4I toward each other. This causes the gates 2I to pivot on the shafts 29, throwing the lower gate members outwardly as shown in Fig. 4. Y

A tension spring 55 has one end attached to lanext'ension 'of one of the pins 53 and the other end fixed to an extension of pin 41. Tension of the spring 55 urges the rotor shaft 50 in a clockwise direction and causes rthe gates 2| to be opened v(that is, with members 23 flared apart as shown in Fig. 4). Closing motion of the gates 2| is limited by abutment `of one of the arms 4I against a stop screw 51. Stop screw 51 is threaded into a lug 59 which is welded to the no'to'r plate 35. A lock nut 6I is lthreaded on stop screw 51 and serves to lock it in suitable position for arresting the gates at the desired amount of gate opening.

Rotation of the motor shaft SI1-in a counterclockwise direction causes the gates 2I to close When the gates are closed, the members 21 are in a substantially vertical position. Closing of the :gates causes the S-shaped flange members 23 Ato project `a considerable distance through the walls I3. The approach or lowermost ends 63 of members 23 project into Arecesses G4, Fig. 7, in vfloor plate "I I, so lthat the trailing end surfaces of members 23 form substantially a, continuation of the top surface of the floor plate I I, when the gates are closed. Closing movement of the Vgates is limited by an adjustable stop screw 65 which is threaded through the arm 21 and is locked in adjusted position by a 'lock nut las shown. The Vend of Yscrew '65 abuts the wall plate 13 when the ngates are closed'.

As previously set forth, the chute 9 and the accompanying parts previously .described may be aow/,799

4 duplicated as many times as required, and the identical units placed one after the other in tandem. Thus as stated, Fig. 1 shows three chutes 9, 9A and 9B in tandem. There may be more or less chutes according to the number oi.' grades to be sorted. The suixes A and B are added to the Various numerals of the chutes 9A and 5B to indicate parts in the second and third units Which are identical with correspondingly numbered parts in the first unit. For example, torque motors 5IA and 5IB are identical with torque motor 5I, et cetera.

Operation of the structure so far described may now be outlined.

Cans are delivered from the cooking equipment or other` source of supply and are passed to the sorting machine on any suitable conveyor. The

- cans, lying on their sides, enter the chute 9 at the left end as seen in Fig. l. One such can is shown entering at 66. This can will roll downward and toward the right, by the force of gravity, along the iioor plate I I.

If the gates 2i are held open by the spring 55, there will be no effect on the progress of the can by contact with members 23. The can will roll the full length of the iioor plate I I and will emergenfrom the mouth 51 of the chute 9. If the motor 5I has been energized to close the gates 2I, the members 23 will project far enough through the wall plates I3 to engage the end periphery of each end of the can as it progresses down the door plate. When the can has rolled down the iloor plate II to contact points 63 of members 23, it rises from the floor plate and follows the track provided by the pair of members 23. The left end of chute 9 is sufficiently high to provide the can with enough momentum to carry it over the rise along the full length of members 23.

When a can leaves the members 23, it enters the chute 9A and begins another descent along the second floor plate IIA. If the gates 2IA are open, the can rolls the full length of plate IIA and emerges at the chute mouth 61A. If the gates 2IA are closed, the can `rolls up over the members 23a and enters the chute 9B. If gates 2I`Ba`reopen, a can entering chute 9B emerges at mouth 61B. If gates 2IB are closed, the can rolls up along vmeml'ners 23B and emerges at the mouth 69. y

The discharge mouths 61, 61A, 61B vand 69 open onto separate suitable conveyors, as indicated in dot and dash lines, which carry the cans to their respective destinations for labeling or other further processing. As will appear below, each Agrade or kind of product emerges from its particular chute mouth according to the locations vof the stripes on the respective cans.

The structure for detecting the presence and location of a stripe on a can and for operating the 'gates accordingly will now be described.

Mounted. on each chute or machine section is a scanning head 1I, 1IA 'and,1IB. In Fig. 6 the head 1I isi-shown with its cover removed to reveal the inner construction and contents. A por- .tion of this headis shown in section for clarity in the explanation. The head 1I is divided into two compartments 13 and '15 by an opaque partitionl 11. -In the compartment 13 is an incandescent lamp 19 and in the compartment 15 is a, .photosensitive electron tube or phototube 8'I, The lamp 19 is held in a conventional socket 83 supported by a bracket which is fixed to the housing of head 1Iby a screw 81. The phototube 8| is held by a socket 89 supported by a bracket 8| fixed to the housing of 1| by a screw 93.

The numerals 95 and 91 indicate convex converging lenses which are supported against apertures in the housing of head 1| by counterbored retaining rings 99 and |0|, respectively. The rings 99 and |0| are secured to the housing of 1| by screws |03.

Light from the lamp 19 passes through the lens 95 and through an aperture |05 in the chute top plate 5. The lens 95 is so constituted and positioned that it forms an image |01 of the lamp filament. The location of this image |01 is slightly below the top plate I5. The image location is such that when the axis of rotation of the rolling can 66 is exactly opposite the partition 11, the image |01 will be sharply formed on the cylindrical surface of the can.

The optical axis of lens 91 intersects that of lens 95 at the image location |01. As a bright portion of a can wall moves through the position (as above described) for sharp formation of the image |01 on the can surface, light is reflected from this image through the lens 91. The lens 91 concentrates the light from the image |01 on the cathode of the phototube 8|. Light reaches the phototube from the image |01 during only a very brief interval in the rolling motion of the can 65. Of course, when there is no can in the chute, no light is reflected therefrom to the phototube. Also, if the image |01 is formed on the dark marking stripe, such as 3, 1 or 8, Fig. 2, of a can, there will be little or no light reflected to phototube 8|.

Referring to Fig. 5, it is seen that the scanning heads 1|, 1|A and 1|B are located in a stepped relation with respect to the width of the machine. That is, head 1| is located nearer the front (lower side in Fig. 5) of the machine than 1|A and 1| B. Also 1| A is nearer the front than 1s 1|B. This stepped relation is such that the light from each head is focused at the designated location for the marking stripe on the cans containing one grade of product. For example, head 1| may be located so that its focus point |01 will fall on the stripe 3 of all cans marked like can in Fig. 2. Head 1|A may be placed to focus light on the stripe 1 of cans marked like can 5, et cetera. Preferably the heads are laterally adjustable so as to direct the focus points as desired, by bolts |08, Fig. 1, cooperable with elongated slots in the head support brackets |09.

Each unit of the machine further includes a switch 329, Figs. l, 3 and 8, screw mounted to a. bracket 328 which is Welded to the motor plate 35. A curved actuating arm 330 is mounted on and rotatable about the axis of a pivot pin 332. The pin 332 is tight in the arm 330 and is journaled in a bracket 334 welded to the bracket 328. An actuating button 336 of the switch 329 is pressed against the actuating arm 330 by a spring (not shown) inside the switch. The arm 330 is adapted to be actuated upwardly or counterclockwise about the pivot 332 by the movement of a can along track or flange members 23, and when the arm 330 is pressed upward (Fig. 6), the switch is actuated to open its contacts. Down- 'ward motion of the arm 330 is limited by an adjustable stop screw 338 threaded through the bracket 328 and held in adjusted position by a lock nut 340.

As a can rolls up along the members 23, it does not touch the arm 330 until it reaches a down- `wardly bent portion of the arm near the end yat 342.

Fig. 9 an electrical diagram, the parts for one unit or chute being shown within the dotted outline 1|. Conductors 20| are three-phase power supply lines. This supply may be of any convenient characteristics such as 230 volts, 60 cycles. A hand disconnect switch 203 is provided to control the connection between the supply lines 20| and conductors 205 Which supply the current to the several units of the machine. The primary winding 201 of a transformer 209 is connected to two of the conductors 205. The purpose of the transformer 209 is to convert the supply voltage of conductors 205 to the usual volts suitable for operation of the electronic circuit components for each of the units, about to be described,

The primary winding 213 of a transformer 2|5 individual to each head is connected by conductors 2|9, 22|, 220 and 222 to the secondary 2|| of transformer 209. The secondary 2|1 of transformer 2|5 is connected by conductors 223, 225, 221 and 229 to the filament 23| of an electron tube 233. The filaments of other tubes and lamps are also supplied with power from the secondary 2|? as follows: through conductors 223, 225, 235 and 231 to the lament of the lamp 19; through conductors 223, 225, 239, 24|, 243 and 245 to the filament 241 of an electron tube 249; and through conductors 223, 225, 239, 24|, 25| and 253 to filament 255 of an electron tube 251. All the filaments mentioned are suitable to receive power at the voltage of the transformer secondary 2|1. As will be understood, the various components Within the broken line 1 Fig. 9, are preferably carried within the unit head structure in any convenient manner.

The primary winding 259 of another head transformer 26| is connected through conductors 2|9 and 22| to the secondary 2|| of transformer 209. One end of the secondary winding 263 of transformer 25| is connected by conductor 265 to one anode 261 of the tube 233. The other end of secondary 263 is connected by conductor 269 to the remaining anode 21| of tube 233. The cathode 213 of the tube 233 is connected by conductor 215 to one end of a resistor 211. The other end of resistor 211 is connected by conductor 219 to the mid-tap of the transformer secondary 263.

Those skilled in the art will recognize that the structure described in the preceding paragraph constitutes a conventional full-Wave rectiner circuit. The tube 233 may be a high vacuum rectifier tube such asfthose used in radio receiving equipment. The resistor 211 is the bleeder or voltage dividing resistor normally used in such circuits. The end of the resistor 211 which is connected to conductor 215 will be the positive end.

A capacitor 28| is connected in parallel with the resistor 211 to provide a partial filtering action.

The phototube 8| is of the Well known photoemissive type. The cathode 283 of this tube is connected by conductor 285 to one end of a resistor 281. The other end of resistor 281 is connected by conductors 289 and 29| to the negative end of the resistor 211. The anode 293 of the phototube 8| is connected by conductor 295 to an adjustable contact 291 on the resistor 211. The contact 291 is set at a point on the resistor 211 to provide a suitable voltage between the anode and cathode of phototube 8|.

The electron tube 249 is a high vacuum trode amplifying tube of the type used in radio receivers. The anode 299 -of the tube 249 'is connected through conductor 30|. a resistor 303 'and conductor 305 to the positive 'end of the resistor 211. The cathode 301 `of the tube 249 is connected by conductor 309 to the movable contact 3|I which -is adjustable Valong a resistor 313.

The resistor -3|3 is connected between 'conh ductor 29| and conductor 24|. Conductor 24| is connected to the contact 3| 5 which is adjustable along the resistor `211 while conductor 29| is cone nect'ed to the `negative end of resistor 211. Thus the voltage across resistor 3|3 is adjustable in value by setting of the contact 3I5. The voltage 'of the cathode 301, relative `to the negative end of the resistor 211, is adjustable conjointly by the 'settings of the contacts '3 I 5 and 3| I. The setting of contact 3I5 determines a maximum value for 'the said cathode voltage land the setting of contact 3I1 determines the actual value beA tween zero and the maximum.

The grid 3|6 of tube 243 is lconnected by con'- du'ctor 311 to conductor .285 which, as previously noted., .forms the connection between the cathode of the phototube 8| and the resistor 281.

When there .is no current flowing in resistor 281, the grid 3 I 6 has the .potential of the negative end of resistor 211. Also, "as previously described, the cathode 301 has an adjustable voltagesomewhat positive with respect to this grid voltage. Stated otherwise, the tube 249 is connected to provide an adjustable vnegative grid bias.

Because of the unidirectional conducting char- -acteristic of the phototube 8l, any current that `does flow in resistor 201 will bein the direction to cause the grid 3I6 `to have a potential positive -with respect -to'cond'ucto'r '291i This potential is opposed to the bias voltage described. This condition aiec'ts' the amount of bias needed when there is more or less 'ambient light on tube Tube2`51 is of the gaseous discharge type commonly refer-red toas a. thyratron tube. The 'anode 43|-9 of tube i251 lis connected by conductor 32| to one end of lthe coil 323 of a relay 325. The other end of the coil 323isconnected by conductor 321'toone terminal of the `switch 329, lpreviously "described,- The other terminal of switch 329 .is connected by conductor 33| and conductor 305 to the positive end of resistor 211. The cathode -333 `ofvtubeA 261 is connected by -conductors 25| and 24| to rthe adjustable' contact 3I-5 of .resistor 211. The screen grid 335 of tube 25.1 -is connected 'to the cathode 333. The control grid 331 of tube 251is connected through a 'resistor 339, 'conductor l34|, 'a resistor 343 conductor 345 and 'conductor :29| to the negative end of resistor 211. A capacitor 341 is connected between conductors 34| and 30|.

The potential on the cathode 333 is positive with respect to the negative end of resistor 211 by an amount determined by the setting of contact 3I5. When there is no current flowing in resistors 339 and 343, the control .grid 331 has the .potential of the negative end 'of 'resistor '211. Thus, the control grid of tube 2'51is negatively biased 'relative to the cathode and the amount of vbias is adjustable by' moving contact 315.

It may be noted that adjustment of contact -3`I5 will a-iect the voltage between the anode fand cathode of tube 251. Also adjustmentof contacts '315 'and -3II will aect the anode-to-cathode potential of tube 249. However, 'the ranges of these Aadjustments are relatively small andthe anode-cathode potential lof these tubes is not critical so 'that the adjustments previously described for grid bias potentials will not adversely affect the anode-cathode potential values.

Operation and adjustment of the photoelectric circuit may now be described. K

With only the normal room light reaching the phototube 3|, the bias setting contacts 3I5 and 3|| are adjusted. Contact 3I5 is set first to provide a negative grid bias which will prevent an ode conduction of the tube 251. Then the contact 3| I is adjusted to prov-ide asuitable low value of anode current in tube 249. Y.

If now there is a momentary hash of light on the cathode of phototube 8 I induced by the ypassage of a can, there will be a momentary increase of current through resistor 281.' This current surge will cause a temporary increase in the posi,- tive potential of the Agrid 3IB with respect to the conductor 23|. As previously pointed out, the potential drop across resistor 281 is opposed to the preset grid bias provided for the tube 249. Consequently, the light flash causes a momentary decrease in the vnegative potential of the grid 313 with respect to the cathode 301 (the grid potential may actually become slightly positive) and there will result a Amomentary increase in the anode current llowing through the resistor 393.

Before occurrence of the above mentioned light flash there lis no current owing through Acapacitor 341 or resistor 343, and so the negative grid bias of tube 251 is as previously described. At this time, however, there is a Vchargeon the capacitor `341 due to the potential dierence b etween the conductor 30| and conductor 23|. The charge on the capacitor is polarizedl positive on the side connected to conductor 30|. l w

When the light ash occurs, the resulting increase of current in resistor 303 causes the conductor 30| to assume a potential less positive with respect to conductor 279|. This reduction of potential causes the capacitor 341 to discharge partially. Thedischarging current hows through the resistor 343 in such a direction as to make the conductor 34| more negative with respect to the conductor 29|. That is, the increase of current in resistor 303 causes an increase in the negative-grid bias on tube 251. No conduction in the anode circuit of tube 251 results from this action.

As the ilash of light is terminated, the momentary increase of current in resistor 303 ceases and the conductor 30| assumes itsoriginal p'otential. The capacitor becomes recharged to its original potential by a momentary current flowing through the resistor 343. This charging current is in such direction as to cause the conductor 34| to become .positive with respect to conductor 279|. This last described potential across resistor v.343 is opposed to the preset grid bias .for tube 251. The result is that the control grid 331 now yassumes a potential less negative (or per- -haps positive) with respect to the cathode 333. The change in grid-to-cathode potential is suincient to permit the anode circuit of the tube 251 to become conducting. l

The anode circuit of tube 4251 is supplied with D. C. potential so that the anode circuit will continue to conduct current even though the grid 331 assumes its original potential as soon as the capacitor 341 is charged back to its original potential. Anode conduction in tube 251 may be stopped by opening the switch 329. This switch opening may be'only momentary. Reclosing of this switch will not start conduction .again because the grid of tube 251 is in condition to prevent conduction at all times except at the instant of a light flash.

I! the anode current in tube 249 changes slowly due to line voltage variations, et cetera, the capacitor 341 will change its charge slowly with very little resulting current through resistor 343. Such slow changes do not cause anode conduction in tube 251. Thus the device 341 is a blocking capacitor which allows only sharp impulses .in the system to start conduction of tube 251.

The current flowing in the anode circuit of tube 251 flows through the winding 323 of the relay 325. This causes the relay to close its contacts 349 and 35|.

Recapitulating, a quick flash of light on and off the cathode of phototube 8| will cause the relay 325 to close and hold closed its contacts T349 and 35|. Slow changes in ambient light inlcident on the phototube 8| will not cause operation of the relay 325 because of the blocking action of capacitor 341.

The torque motor is preferably wound for three-phase current supply. As is familiar to those skilled in the art, a torque motor has the characteristic of producing its highest torque when the rotor shaft is held stationary. Such motors are intended for actuation of mechanisms which stall the motor at the end of the actuation.

The stator windings of motor 5| have one terminal connected by conductor 353 to one of the conductors 205. The other two motor terminals are connected by conductors 355 and 351 to the contacts 349 and 35|, respectively, of the relay 325. The remaining sides of the contacts 349 and 35| are connected to the remaining conductors 205.

When the contacts 349 and 35| are closed by energization of the coil 323 of relay 325, current is conducted to the motor 5| which then exerts a torque.

As seen in Fig. 4, and as previously described, when the motor 5| is not energized the spring 55 holds the arm 4| against the stop screw 51 and the gates 2| stand open. When power is applied to the windings of motor 5|, the rotor shaft 50 turns counterclockwise (Fig. 3). This acts through crank arm 49 and links 45 to force the arms 4| outward, closing the gates 2|. Closing motion is stopped by abutment of stop screw 65 against the wall member |3. Continued energization of the motor 5| keeps the gates closed. When the motor is electrically disconnected, the .spring 55 again opens the gates 2|.

We may now review the general operation of the can sorting device.

Let it be assumed that a can 66 has been introduced into the left end, Fig. 1, of the chute 9 and has rolled down to approximately the position it occupies in Fig. 6. As the can rolls 'through this position, light lis momentarily re- :flected to the cathode of phototube 8| if the can wall is bright at the point |01 where light is `focused from the lamp 19. This flash of light results in the operation of relay 325 which causes the motor 5| to be energized. Motor 5| closes the gates 2|. When the can has rolled to the point 63, it rolls up on the flange members 23 of gates 2| and enters the chute 9A, Fig. l. As the can leaves the right end of members 23, it raises the lever 33!! causing the contacts of switch 329 to open and deenergize the relay 325. This deenergizes the motor 5| and the gates 2| open ready for another can.

If when the can reached the focus point |01, there was a dark stripe on the portion of the can on which the light fell, there would be no flash of light to the phototube. In such case the `gates 10 2| would not close and the can would roll out the mouth 61.

Any can which rolls up over the gate flanges when the gates are closed enters chute 9A, and the operations there are the same as for chute 9. According to location of the dark stripes, the can may emerge at mouth 61A or it may go on to chute 9B where a further selection is made.

As previously described, there may be as many sections or chutes as required by the number of grades to be distinguished.

In the last section, such as 9B, the upper or closed gate mouth 69 may be used for a definite grade or it may be used as a rejection exit for cans which have failed to receive a stripe through some error in marking. Unmarked cans will emerge at the exit mentioned because such a can is bright all over and will cause all the gates to close in sequence as it goes through.

In the marking of the cans, as previously described in reference to Fig. 2, it is necessary that the end-for-end orientation of the cans be preserved so that the marking stripes will be properly presented. In Fig. 2A an arrangement is illustrated wherein duplicate marking stripes 3a and 8a are provided at each end of the can, in the positions of the stripes 3 and 8 previously described. In such instance it is clear that the end-for-end orientation of the cans need not be preserved, and the cans may be twisted or stored in any desired manner prior to transmission to the can sorting machine.

It is obvious that various changes may be made in the specific embodiments of the invention set forth for purposes of illustration, without departing from the spirit thereof. The invention is accordingly not to be limited to the specific embodiments shown and described, but only as indicated in the following claims.

The invention is hereby claimed as follows:

1. A sorting machine for cans or the like having visual indicia. thereon, and comprising a plurality of conveyor sections each including a downwardly inclined conveyor trackway along which the cans or the like to be sorted are rolled in sequence and a divergent conveyor trackway inclined upwardly from the conveyor trackway for communication with the next succeeding conveyor section, a light sensing device located adjacent each conveyor section and each sensing device being disposed with respect to its conveyor section in a position laterally different from that of the sensing device for an adjacent conveyor section and predetermined in accordance with the applied indicia on the cans or the like being passed, and a gate device for each conveyor section operable in response to its sensing device to be positioned to afford communication between the inclined conveyor trackway and the divergent conveyor trackway to permit articles with predetermined indicia thereon to pass through the communicant conveyor trackway and the divergent conveyor trackway.

2. A sorting machine as claimed in claim 1, wherein a switch mechanism is disposed within the divergent conveyor trackway to release the gate device upon the passage of a can or the like therethrough for affording through communica tion along the conveyor trackway.

3. A sorting machine as claimed in claim l, wherein the gate device includes complemental gate members shiftable into and out of the path of movement of a can or the like along the conveyor trackway.

4. A sorting machine as claimed in claim 1,

wherein the divergent conveyor trackway-is substantially S-shaped and wherein the gate device includes,k complemental- S-shaped gate-*members forming a trackway for the divergent conveyor trackway and shiftable into and out of the path of movement of a can or the like along the conveyor tracliway.

5. A sorting machine as claimed in claim 1, wherein the sensing device includes aV photo cell and a relay responsive to the rate of energy change of the photo cellwthin a given energy range.

6. A sorting `machine as claimed in claim 1, wherein thev light sensing device includes a photo cell, an amplifier responsive to the action of the photo cell, a relay controlled by theamplier, and a rotary armature torque motor controlled by the relay.

FREDERICK M'. JOHNSON. LEANDER J. BULLIET;

References- Citedin the 'l'e of this patent UNITED STATES PATENTS Number Name DateY Hudd-leston Nov. 20, 1917 Bryce May 1, 1928 'Gammell June 2, 1931 Sworykin Aug. 15, 1933 Sworykin Nov. 6, 1934 Mauly May 7, 1935 MooreV Feb. 9, 1937 Gulliksen O ct. 19,1937 Flint` Jan. 20, 1942 Henszey Jan. 18, 1944 Hurley Feb. 26,1946 

